package com.itheima02.day02test;

/**
 * @author 刘全
 * @date 2021/7/16
 */
public class Computer {
    public void powerOn(){
        System.out.println("笔记本开机");
    }
    public void useUsb(USB u){
        u.open();
        u.close();
    }
    public void powerOff(){
        System.out.println("笔记本关机");
    }
}
